Some of the most vulnerable children in Britain are at risk because of a nationwide shortage of suitable social workers, the co-president of the Association of Directors of Children's Services has warned.

In some parts of the country, the shortage is so bad that local authorities are paying for officials to travel abroad to find experienced staff. Other councils have resorted to paying new employees 'golden hellos' and awarding bursaries to undergraduates to encourage them to complete their social work degrees.

'There is an overall shortage of qualified children's social workers across Britain and that shortage is particularly felt in the most complex of cases, involving the care of children in care, children with severe disabilities and those working in child protection,' said John Coughlan, who is also director of children's services at Hampshire county council. 'Obviously, this shortage could create risks for those children.'

There is no central record of the level of shortages, but Coughlan says the problem is widespread. He points to the situation in Birmingham as representative of urban areas across the country. The city has 16 vacancies despite extensive efforts to fill them. The situation is so acute that its vulnerable children overview and scrutiny committee has recently been forced to introduce three recruitment initiatives and is considering more. 'Some undergraduates studying social work in Birmingham now receive funding for their final year at university, while any qualified social worker will be awarded a bonus of £1,000 at the end of their first year of work here,' said the committee chairman, Keith Barton.

The council recently sent three members of staff to America to interview qualified social workers, resulting in the hiring of 14 who will soon start work. Despite that success, Barton is still concerned. Committee members met again last week to discuss recruiting and retaining staff. 'We are considering funding undergraduates through their entire course, instead of just supporting them in their final year,' he said. 'We will be as imaginative, innovative and determined as it is necessary to get numbers back up to a level that means this city's most vulnerable children will be safe.'

Coughlan fears that high staff turnover and low recruitment are due to the high emotional stress of the job, as well as low salaries. 'This is a career where employees not only work extremely hard in situations of extreme emotional stress, but they frequently get publicly pilloried into the bargain,' he said.

This criticism centres on cases where social workers have failed to protect children in their care. There has been at least one report on the death of a child whose killers were known to social services in every year since 1997. These include the murder of Leticia Wright, the four-year-old in Huddersfield, West Yorkshire, battered to death in November 2006 by her mother and her boyfriend, despite being both visited and monitored.

'I have heard of local authorities recruiting from Eastern Europe, America, New Zealand, Australia and Canada,' said Coughlan. 'These people have to be retrained, but there's an additional problem in the case of Eastern Europe. The last thing we want is to create a situation where other countries no longer have enough workers to care for their children, because those people have been encouraged to come to Britain.'